Building a front loader frame

I bought a front loader, but my tractor didn't have a suitable loader frame to attach the loader to. So I had to build a loader frame.
Luckily my tractor had quite a few large threaded holes that could be used to fasten the loader frame. I used thick angle iron to create the base frame and gussets were used to reinforce load bearing points. A square tube with reinforcement plates was used for the upright posts.
I first tried to use angle iron to support the upright posts, but it proved to be too weak and was replaced with the same square tube material that was used in the upright post.
Everything was painted with a primer. I'm planning on painting the whole tractor after a few months, so the primer will do until then.
The main use for this front loader will be to move snow in the winter. However I have already tried it with a full bucket of gravel, so I think it will be durable enough.